1. Field of the Invention
This invention relates to wooden bars arranged on keyboards or frames of percussion instruments such as xylophones and marimbas.
2. Description of the Related Art
Generally, percussion instruments such as xylophones and marimbas have arranged multiple types of wooden or metal bars having different lengths on keyboards or frames, and players play these instruments by striking the bars with small hammers or mallets. Sounds produced by striking the bars resonate with designated pitches, which depend on the lengths of the bars.
As materials for use in the bars of the aforementioned percussion instruments, it is possible to use hardwood materials such as rosewoods, hard birches, padauks, and Chinese quinces as well as fiber reinforced plastics (FRP) such as carbon fiber reinforced plastics (CFRP) and glass fiber reinforced plastics.
Japanese Unexamined Patent Publication No. Sho 60-159894 discloses an example of a bar-type percussion instrument using wooden bars having specific frequencies arranged on a keyboard or frame, wherein as shown in FIGS. 5A and 5B, a hollow 11 is formed on the center of the backside of a wooden bar 10, so that the wooden bar 10 is tuned in such a way that the frequency ratio (i.e., a ratio between numbers of vibrations per unit time) in either the basic mode or high-order mode is increased to be substantially multiple times higher. This guarantees clear pitches (or intervals) in producing percussion sounds by striking bars with a mallet or the like.
Since the aforementioned bar is made of the prescribed wooden material, it may be superior in sound quality and (exterior) design. However, this bar has a relatively small thickness at the center portion corresponding to the formation of the hollow thereof and is fragile when struck with a mallet or the like. That is, there is a possibility that the bar may be easily broken or damaged due to fatigue caused by being repeatedly struck. In particular, a lower-pitch bar shown in FIG. 5B is greatly reduced in thickness at the center portion thereof compared with a higher-pitch bar shown in FIG. 5A. That is, the lower-pitch bar is easily broken or damaged by being repeatedly struck compared with the higher-pitch bar. When the bars arranged in the bar-type percussion instrument are partially broken or damaged, it may be necessary to replace the broken or damaged bars with new ones, or it may be necessary to tune the bar-type percussion instrument again. This causes problems in incurring additional cost and wasting time in the replacement of parts and tuning.
Japanese Unexamined Patent Publication No. Sho 51-127712 discloses another example of bars for use in percussion instruments, wherein bars are made of fiber reinforced plastics. That is, bars are produced by cutting fiber reinforced plastic materials into bars each having a prescribed shape. Since fiber reinforced plastic materials are hardly affected by weather conditions such as temperature and humidity, these bars are advantageous because they can be manufactured with uniform quality.
The bars made of fiber reinforced plastics may be highly improved in durability against striking; however, the player may experience a ‘hard’ striking feeling when striking these bars with a mallet. In addition, these bars have some drawbacks in sound quality because they produce only hard sounds and lack softness or mellowness, particularly in low pitch ranges. Since these bars are made of plastics, their exterior surfaces may lack luxuriousness in appearance and may be inferior in design. In addition, the bars made of fiber reinforced plastics may not be easily mechanically processed. Therefore, unlike the foregoing wooden bars as disclosed in Japanese Unexamined Patent Publication No. Sho 60-159894, these bars made of fiber reinforced plastics are hardly improved in sound quality by forming hollows on the undersides thereof.
Japanese Unexamined Patent Publication No. Sho 51-127712 also discloses another type of bar in which a wooden base layer is sandwiched between fiber reinforced plastic layers, which form exterior surfaces (sec FIG. 4). This bar may be improved in sound quality because the sound may efficiently propagate in the air and is retained for a relatively long time. However, when a hollow is formed in the underside of the bar, the aforementioned improvement in the sound quality may substantially vanish